Engine starter drive



July 12, 1960 J. E. ANToNlDls ET AL 2,944,427

ENGINE STARTER DRIVE ,W 55 l, mwM m MNM.. o v0 T WWCMT @im A 554W vm w ODAA J Y B i 2,944,427 Patented July 12, 1960 ENGmE STARTER DRIVE John E. Antonidis andV Robert A. Ulm, Anderson, Ind., assignors to General Motors A Corporation, Detroit, Mich., a corporation of Delaware Filed June 1o, 1951, ser. No. 664,803

s claims. (01.74-7) This invention relates to starter drives for internal combustion engines and is more particularly concerned with starter drives of the type wherein the pinion gear is propelled by its own' inertia into meshing engagement with a gear connected with the engine to be started.

- It is an object of the present invention to provide a simple, economical inertia type starter drive wherein a pinion which is movable on a threaded starter shaft will move to and` from a cranking position `without shock.

A further object of the present invention is to combine a starter drive with a reversible electric motor which has an axially movable threaded shaft. K'This arrangement will permit the shaft to move axially to relieve tooth end abutment when the pinion is prevented from passing into meshing engagement with an engine gear andvto crank the engine in either direction.

Another object of the present invention is to provide a starter drive with an independently movableV pinion gear and ya means to absorb the shock of engagement between the pinion gear and the gear connected with Vthe engine to be started which means includes a resilient stop which is disposed on the side of the engine gear which is opposite to the pinion gear side.

A still further object of the present invention is to provide a starter drive which will crank an engine in either direction of rotation and to provide a pair of rubber-like thrust members between the motor shaft and the motor frame to allow limited axial movement on the shaft in either direction so that tooth end abutment between the pinion gear and the engine gear will be relievedy when the pinion is propelled and is prevented from passing into meshing engagement.

It is another object of the present invention to provide each of a pair of pinions ofa double acting starter drive, which is used with a reversible motor and wherein the pinions are disposed on opposite sides of a ring gear, with resilient bumpers which will absorb the shock which accompanies the meshing engagement of the pinions with the ring gear. l

lFurther objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein preferred embodiments of the present invention are clear- In the drawings:

Figure 1 is a view, partly in section, showing a motor and starter drive arrangement according to the present invention.

Figure 2 is a View, partly in section, showing the position of the various parts of the starter drive in Figure l when one of the pinions is in meshing engagement with the ring gear of the engine to be cranked.

Figure 3 is a view taken along line -3 in Figure l.

'Figure 4 is a view taken along line 4 4 in Figure l.

Figure 5 is a view of a modification of the starter drive in Figure 1.

lThe starter drive arrangement shown in Figure l of the drawings is actuated by the motor 20. The motor 20 has a rotor 22 supported by the shaft 24 that is suitably journalled in .the end frames 26 and 28 of the motor 20. The motor, 20, in the embodiment shown in Figure 1, has its iields 30 preferably wound so the rotor 22 will'rotate in either direction.

The shaft 24 is formed with an'integrally threaded or splined portion 32 which extends exterior to the housing of the motor 20. The shaft 24 is also slightly axially movable relative to the housing and is yieldably held in a normal neutral position against movement in either direction by the annular resilient thrust members 34 and 36r The members 34 and 36 are formed of resilient rubber-like material and are positioned between the end frames 26 and..28 and thrust washers 38 and 40 respectively. The thrust washers 38 and 40 are arranged to permit the shaft 24 to rotate in the housing without imparting the rotation of the shaft to the thrust members 34 and 36.

-Threadably rotatable on the threads or splines 32 of the shaft 24 and disposed on opposite sides of the ring gear 42 of the engine tobe started are pinion gears 44 and 46. The pinion gears 44 and 46 together with the parts whichwill be hereinafter described are each identical and therefore only the gear 44 and the parts connected therewith will be described.

Located at each end of the threaded portion 32 of the shaft24 are stops 48. These stops may be conventional and, in the `embodiments shown, may consist of a hard metal annulus 50 which has an inner groove wherein a snap ring 52 is received. `The ring 52 is received and held in position by the annular groove in the shaft 24 at the positions indicated. Positioned between the stop 48 and the pinion gear 44 is a shock absorbing means or bumper S4 which consists of a pair of washers 56 and 58 which are located on opposite sides of an annulus 60 which is formed of rubber-like material. The metal washers 56 and 58 and the annulus 60 each have their inner openings sized to freely pass over the threaded portion B2. The pinion gears 44 and 46 are normally held in the position shown in Figure l by torsion springs 62 which have one end secured to a hole in one of the teeth of the pinion at 64 as shown -in Figure 3 and the other end resting in an annular groove 66 and extending into a hole 68 in shaft 24 as shown in Figure 4. When the shaft is rotated, either one of the pinion gears will be moved depending on the direction of rotation of the shaft 24. When the shaft is rotated in the proper direction to cause movement of the pinion gear 44, the pinion gear 44 will move from the position shown in Figure l to the right to the position shown in Figure 2 where the pinion gear 44 is in engagement with the ring gear 42 for cranking purposes. y.This movement of the pinion gear 44 to the right .is accomplished because of its inertia against rotation. Thus, when the shaft 24 is initially rotated, the pinion gear, because of its inertia, will not rotate with the shaft but will be axially propelled along the shaft toward the ring gear 42. In the event tooth abutment occurs between the pinion gear 44 and the ring gear 42, the shaft 24 will move slightly to the left, such movement being opposed by annular rubber member 34 as it is compressed between washer 38 and end frame 26. IThis will permit the pinion gear to be slightly rotated to relieve the tooth abutment. When the pinion gear `44 moves into mesh with the ring gear 42 and engages the pinion gear 46., the shock of the engagement will be absorbed by the rubber annulus 60 which is associated with the pinion gear 46. After the engine has become self-operative and pinion gear 44 is rotated faster than the rotational speed of the shaft 24, the pinion gear will be propelled to the left to the at-rest position. This movement is aided by the torsion spring y62 which has been stretched and tightened during the period when the pinion moved into crankingv engagement. The shock which accompanies the return of the pinion from the position shown in FigureA 2 to the position shown in Figure 1 is absorbed by the rubber bumper means 5-4 which is associated with the pinion 44.

When the shaft '24 is rotated in the` opposite direction by the motor 20, the pinion gear 46 will be moved into meshing engagement with the ring gear 42 and will engage the gear 44 in a manner as described above, In the event that tooth abutment occurs between the pinion gear 46 and the gear 42, the washer `4t) and the rubber member 36 will permit a slight axial movement of the shaft 24 to the right to relieve the tooth abutment. As was precedingly described, when the pinion gear 46 is moved into the meshing'engagement, it engages the pinion gear 44. The force of this engagement is absorbed by the rubber bumper 54.

VIn Figure 5 of the drawings, a modification of the starter drive, Aaccording to the present invention, is shown. In this embodiment, the motor, not shown,`will rotate shaft 70 in one direction only. The shaft 70, which extends external to the motor housing, has spiral threads formed thereon. As clearly seen in the drawing, .the pinion 72 and absorbing bumper 84 are spaced from each other on opposite sides of the ring gear 76 of the engine to be started. As described in the preceding embodiment, the pinion gear 72 is normally held in its retracted position by a torsion spring which is under slight tension and which isV wrapped around the shaft and has one of its ends secured in an annular groove 78. The torsion spring is secured in one of theteeth of the pinion 72 as in the preceding embodiment. The pinion `stop 79, which is preferably formed of hard metal, is held in position by the ring 80 that is received in the grooves in the shaft and pinion stop. The bumper 74 includes a washer 82, an annular member 84 which is formed of rubber-like material and a stop member 86 which is held in position on the shaft 24 by means of a snap ring 88 that is received between the annular groove which is suitably located in the shaft and the groove which is located in the stop member 86 as shown. The annular member is held under slight compression between the washer 82 and the stop member 86 by means of a shell 90 which has its respective ends 94 and 96 turned over the outer face of the washer 82 and the stop member 86.'

From the above arrangement, it is apparent that when the shaft is rotated, the pinion 72 will be propelled. `to

the right against the force of the torsion springv into meshing engagement with the ring gear4 76. The shock which accompanies this meshing engagement is absorbed when the edge 98 of the pinion engages the outer surface of the washer S2 to slightly compress the annnular member 90. After the engine becomes self-operative, the pinion gear will rotate faster than the shaft 70 and move to the left as described in the preceding embodiment. In this embodiment, only one of the thrust members which will permit axial movement of the shaft 70 is required; and the thrust member 36 and the washer 40 may be eliminated. Further, it is apparent when the pinion 72 is prevented, because of tooth end abutment, from moving into mesh with the ring gear 76, the thrust member, similar to that shown as 34 in Figure 1, will permit the shaft to move slightly to the left to relieve the tooth abutment.

While the forms of embodiment of the present invention as herein disclosed constitute preferred forms, it is to be understood that other formsrmight be adopted.

What is claimed is as follows:

1. In a starting apparatus for an internal combustion engine, the combination comprising; a motorl including"4 a housing, la rotor and a shaft, rotatable by said .rotor 4 in either direction, said shaft having a limited axial movement in said housing and an end projecting exterior to said housing having an integral threaded portion, a stop means xed to the shaft located adjacent the respective ends of the threaded portion, a pair of pinion gears in threaded engagement with the threaded portion and normally spaced from each otheron `opposite sides of a gear connected to the engine to be started, resilient means disposed between the pinion gears andstops, a pairY of spring means each having an end connected tothe shaft and an endv connected to onev ofthe pinions for constantly opposing the movement of the pinions toward the engine gear, and a resilient means between the shaft and housing forpermitting the, limited axial movement of the shaft in the housing when the shaft is rotated and the pinion gear moves into'tooth abutment with the engine gear.

2. In a starting apparatus for an internal combustion engine, the combination comprising; aV motor including; a housing, a rotor and a shaft rotatable in either direction of rotation in said housing by said rotor, said4 shaft having a limited axial movement relative to the housing and an integral threaded, end portion projecting external to the housing, a p air of pinions threadedly engaging the threaded portion of the shaft and spaced on opposite sides of a gear connectedY with anl engine to be started, s'aid pinions being adapted to b e. selectively moved into engagement with the gear when the shaft is rotated in either direction, resilient stops on the respective ends` of the threaded portions ofr theshaft arranged to limit the spacing between the pinions, means for constantly urging the pinions against the stops, and yieldable means between the shaft and housing for permitting the limited axial movement of the shaft in either direction when either one of the pinions is movedptoward the gear and is prevented froml moving into meshingv engagement therewith.

3. In a starting apparatus for an internal combustion engine the combination comprising; a starting motor in-l cluding; a housing, a rotor, a shaft rotatable by the vrotor andv having a limited axial movement relative to the housing, an integral threaded portion on said shaftl projecting exterior to said housing; a pinion gear in threaded engagement with said shaft arrangedY to be axially propelled thereon into meshing engagement witha gear connected tothe engine to be startedhwhenever, the shaft is initially rotated, a stop means on the end of the threadedy portion adjacent the motor for limitingthe travel of the pinion in one direction, a torsion spring having one end connected to the shaft and the other end connected to the pinion 4forrconstantly urging said pinion towardfsaid stop andfrom said meshing engagement, a resilient stop iixed to the shaft on the other end of the threaded portion arranged to absorb shock to the pinion when said pinion is moved into the meshing engagement and a resilient means between the shaft and housing arranged to permit the shaft to move axially away from the` gear when thepinion is prevented from moving into `mesh with the enginey gear. i

4. Ina starting apparatus for an internal combustion engine, the combination` comprising;` a starting motor including; a housing, a rotor and a shaft rotatable by the rotor in either direction, and having, a limited axial movementrelative to the housing, a threaded portion integrally formed in the shaftv exterior to the housing, aV

pair of piniongears threadedly engaging the threaded portion of the shaftand spaced from one vanother on opposite sides of a gear connected to an engineto be threaded portion, resilient means disposed:between1111?`Vv respective Vpinions and` xedv. stops." for absorbingy shock www.,

when the pinion is moved from the meshing engagement, a pair of torsion springs each having an end connected with one of the pinions and an end connected to the shaft for constantly urging the pinions toward the respective resilient means and fixed stops, and from the meshing engagement with the ring gear, said stops and resilient means being arranged on the shaft to space the pinions on opposite sides of the ring gear so the resilient means associated with one of the pinions will absorb the shock of engagement of the other pinion when the other pinion is propelled by the rotation of the shaft `and a resilient means between the housing and shaft arranged to permit the shaft to axially move a limited distance in either direction whenever either one of the pinions is propelled by the shaft and prevented from moving into the meshing engagement.

5. The combination as set forth in claim 4 wherein the housing is provided with a pair of end covers and the resilient means between the shaft and housing includes a pair of annular rubber-like members which are arranged to resiliently maintain the shaft in position relative to the housing.

6. The combination as set forth in claim 4 wherein the resilient means disposed between the pinion gears and fixed stops includes a pair of metal annular members which are disposed on opposite sides of an annular rubber-like member and wherein all of the annular members are slidable on the threaded portion of the shaft.

7. In a starting apparatus for an internal combustion engine, the combination comprising; a rotatable shaft,

a pinion gear, resilient means axially spaced from said pinion gear for taking up shock when Said pinion gear is propelled into meshing position, a torsion spring having one end thereof connected to and engaging said shaft and having a portion engaging said pinion gear for urging said pinion gear in one direction, threaded means forming a driving connection between said shaft and said pinion gear for causing said pinion gear to be advanced along said shaft against the bias of said torsion spring when said shaft is rotated, an annular groove formed in said shaft, a rst annular member positioned within said groove, and a second annular member fitted over said 1irst annular member and having `an internal wall engaging said first annular member, said second annular member constituting a positive stop for said pinion gear through said resilient means.

8. Starting apparatus according to claim 7 wherein the vshaft has integral threads that form a part of the said threaded means.

References Cited in the iile of this patent UNITED STATES PATENTS 

